1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * devfreq: Generic Dynamic Voltage and Frequency Scaling (DVFS) Framework
   4 *	    for Non-CPU Devices.
   5 *
   6 * Copyright (C) 2011 Samsung Electronics
   7 *	MyungJoo Ham <myungjoo.ham@samsung.com>
   8 */
   9
  10#include <linux/kernel.h>
  11#include <linux/kmod.h>
  12#include <linux/sched.h>
  13#include <linux/debugfs.h>
  14#include <linux/devfreq_cooling.h>
  15#include <linux/errno.h>
  16#include <linux/err.h>
  17#include <linux/init.h>
  18#include <linux/export.h>
  19#include <linux/slab.h>
  20#include <linux/stat.h>
  21#include <linux/pm_opp.h>
  22#include <linux/devfreq.h>
  23#include <linux/workqueue.h>
  24#include <linux/platform_device.h>
  25#include <linux/list.h>
  26#include <linux/printk.h>
  27#include <linux/hrtimer.h>
  28#include <linux/of.h>
  29#include <linux/pm_qos.h>
  30#include <linux/units.h>
  31#include "governor.h"
  32
  33#define CREATE_TRACE_POINTS
  34#include <trace/events/devfreq.h>
  35
  36#define IS_SUPPORTED_FLAG(f, name) ((f & DEVFREQ_GOV_FLAG_##name) ? true : false)
  37#define IS_SUPPORTED_ATTR(f, name) ((f & DEVFREQ_GOV_ATTR_##name) ? true : false)
 
  38
  39static struct class *devfreq_class;
  40static struct dentry *devfreq_debugfs;
  41
  42/*
  43 * devfreq core provides delayed work based load monitoring helper
  44 * functions. Governors can use these or can implement their own
  45 * monitoring mechanism.
  46 */
  47static struct workqueue_struct *devfreq_wq;
  48
  49/* The list of all device-devfreq governors */
  50static LIST_HEAD(devfreq_governor_list);
  51/* The list of all device-devfreq */
  52static LIST_HEAD(devfreq_list);
  53static DEFINE_MUTEX(devfreq_list_lock);
  54
  55static const char timer_name[][DEVFREQ_NAME_LEN] = {
  56	[DEVFREQ_TIMER_DEFERRABLE] = { "deferrable" },
  57	[DEVFREQ_TIMER_DELAYED] = { "delayed" },
  58};
  59
  60/**
  61 * find_device_devfreq() - find devfreq struct using device pointer
  62 * @dev:	device pointer used to lookup device devfreq.
  63 *
  64 * Search the list of device devfreqs and return the matched device's
  65 * devfreq info. devfreq_list_lock should be held by the caller.
  66 */
  67static struct devfreq *find_device_devfreq(struct device *dev)
  68{
  69	struct devfreq *tmp_devfreq;
  70
  71	lockdep_assert_held(&devfreq_list_lock);
  72
  73	if (IS_ERR_OR_NULL(dev)) {
  74		pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
  75		return ERR_PTR(-EINVAL);
  76	}
  77
  78	list_for_each_entry(tmp_devfreq, &devfreq_list, node) {
  79		if (tmp_devfreq->dev.parent == dev)
  80			return tmp_devfreq;
  81	}
  82
  83	return ERR_PTR(-ENODEV);
  84}
  85
  86static unsigned long find_available_min_freq(struct devfreq *devfreq)
  87{
  88	struct dev_pm_opp *opp;
  89	unsigned long min_freq = 0;
  90
  91	opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &min_freq);
  92	if (IS_ERR(opp))
  93		min_freq = 0;
  94	else
  95		dev_pm_opp_put(opp);
  96
  97	return min_freq;
  98}
  99
 100static unsigned long find_available_max_freq(struct devfreq *devfreq)
 101{
 102	struct dev_pm_opp *opp;
 103	unsigned long max_freq = ULONG_MAX;
 104
 105	opp = dev_pm_opp_find_freq_floor(devfreq->dev.parent, &max_freq);
 106	if (IS_ERR(opp))
 107		max_freq = 0;
 108	else
 109		dev_pm_opp_put(opp);
 110
 111	return max_freq;
 112}
 113
 114/**
 115 * devfreq_get_freq_range() - Get the current freq range
 116 * @devfreq:	the devfreq instance
 117 * @min_freq:	the min frequency
 118 * @max_freq:	the max frequency
 119 *
 120 * This takes into consideration all constraints.
 121 */
 122void devfreq_get_freq_range(struct devfreq *devfreq,
 123			    unsigned long *min_freq,
 124			    unsigned long *max_freq)
 125{
 126	unsigned long *freq_table = devfreq->freq_table;
 127	s32 qos_min_freq, qos_max_freq;
 128
 129	lockdep_assert_held(&devfreq->lock);
 130
 131	/*
 132	 * Initialize minimum/maximum frequency from freq table.
 133	 * The devfreq drivers can initialize this in either ascending or
 134	 * descending order and devfreq core supports both.
 135	 */
 136	if (freq_table[0] < freq_table[devfreq->max_state - 1]) {
 137		*min_freq = freq_table[0];
 138		*max_freq = freq_table[devfreq->max_state - 1];
 139	} else {
 140		*min_freq = freq_table[devfreq->max_state - 1];
 141		*max_freq = freq_table[0];
 142	}
 143
 144	/* Apply constraints from PM QoS */
 145	qos_min_freq = dev_pm_qos_read_value(devfreq->dev.parent,
 146					     DEV_PM_QOS_MIN_FREQUENCY);
 147	qos_max_freq = dev_pm_qos_read_value(devfreq->dev.parent,
 148					     DEV_PM_QOS_MAX_FREQUENCY);
 149	*min_freq = max(*min_freq, (unsigned long)HZ_PER_KHZ * qos_min_freq);
 150	if (qos_max_freq != PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE)
 151		*max_freq = min(*max_freq,
 152				(unsigned long)HZ_PER_KHZ * qos_max_freq);
 153
 154	/* Apply constraints from OPP interface */
 155	*min_freq = max(*min_freq, devfreq->scaling_min_freq);
 156	*max_freq = min(*max_freq, devfreq->scaling_max_freq);
 157
 158	if (*min_freq > *max_freq)
 159		*min_freq = *max_freq;
 160}
 161EXPORT_SYMBOL(devfreq_get_freq_range);
 162
 163/**
 164 * devfreq_get_freq_level() - Lookup freq_table for the frequency
 165 * @devfreq:	the devfreq instance
 166 * @freq:	the target frequency
 167 */
 168static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
 169{
 170	int lev;
 171
 172	for (lev = 0; lev < devfreq->max_state; lev++)
 173		if (freq == devfreq->freq_table[lev])
 174			return lev;
 175
 176	return -EINVAL;
 177}
 178
 179static int set_freq_table(struct devfreq *devfreq)
 180{
 
 181	struct dev_pm_opp *opp;
 182	unsigned long freq;
 183	int i, count;
 184
 185	/* Initialize the freq_table from OPP table */
 186	count = dev_pm_opp_get_opp_count(devfreq->dev.parent);
 187	if (count <= 0)
 188		return -EINVAL;
 189
 190	devfreq->max_state = count;
 191	devfreq->freq_table = devm_kcalloc(devfreq->dev.parent,
 192					   devfreq->max_state,
 193					   sizeof(*devfreq->freq_table),
 194					   GFP_KERNEL);
 195	if (!devfreq->freq_table)
 
 196		return -ENOMEM;
 
 197
 198	for (i = 0, freq = 0; i < devfreq->max_state; i++, freq++) {
 199		opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
 200		if (IS_ERR(opp)) {
 201			devm_kfree(devfreq->dev.parent, devfreq->freq_table);
 
 202			return PTR_ERR(opp);
 203		}
 204		dev_pm_opp_put(opp);
 205		devfreq->freq_table[i] = freq;
 206	}
 207
 208	return 0;
 209}
 210
 211/**
 212 * devfreq_update_status() - Update statistics of devfreq behavior
 213 * @devfreq:	the devfreq instance
 214 * @freq:	the update target frequency
 215 */
 216int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
 217{
 218	int lev, prev_lev, ret = 0;
 219	u64 cur_time;
 220
 221	lockdep_assert_held(&devfreq->lock);
 222	cur_time = get_jiffies_64();
 223
 224	/* Immediately exit if previous_freq is not initialized yet. */
 225	if (!devfreq->previous_freq)
 226		goto out;
 227
 228	prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
 229	if (prev_lev < 0) {
 230		ret = prev_lev;
 231		goto out;
 232	}
 233
 234	devfreq->stats.time_in_state[prev_lev] +=
 235			cur_time - devfreq->stats.last_update;
 236
 237	lev = devfreq_get_freq_level(devfreq, freq);
 238	if (lev < 0) {
 239		ret = lev;
 240		goto out;
 241	}
 242
 243	if (lev != prev_lev) {
 244		devfreq->stats.trans_table[
 245			(prev_lev * devfreq->max_state) + lev]++;
 246		devfreq->stats.total_trans++;
 247	}
 248
 249out:
 250	devfreq->stats.last_update = cur_time;
 251	return ret;
 252}
 253EXPORT_SYMBOL(devfreq_update_status);
 254
 255/**
 256 * find_devfreq_governor() - find devfreq governor from name
 257 * @name:	name of the governor
 258 *
 259 * Search the list of devfreq governors and return the matched
 260 * governor's pointer. devfreq_list_lock should be held by the caller.
 261 */
 262static struct devfreq_governor *find_devfreq_governor(const char *name)
 263{
 264	struct devfreq_governor *tmp_governor;
 265
 266	lockdep_assert_held(&devfreq_list_lock);
 267
 268	if (IS_ERR_OR_NULL(name)) {
 269		pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
 270		return ERR_PTR(-EINVAL);
 271	}
 272
 273	list_for_each_entry(tmp_governor, &devfreq_governor_list, node) {
 274		if (!strncmp(tmp_governor->name, name, DEVFREQ_NAME_LEN))
 275			return tmp_governor;
 276	}
 277
 278	return ERR_PTR(-ENODEV);
 279}
 280
 281/**
 282 * try_then_request_governor() - Try to find the governor and request the
 283 *                               module if is not found.
 284 * @name:	name of the governor
 285 *
 286 * Search the list of devfreq governors and request the module and try again
 287 * if is not found. This can happen when both drivers (the governor driver
 288 * and the driver that call devfreq_add_device) are built as modules.
 289 * devfreq_list_lock should be held by the caller. Returns the matched
 290 * governor's pointer or an error pointer.
 291 */
 292static struct devfreq_governor *try_then_request_governor(const char *name)
 293{
 294	struct devfreq_governor *governor;
 295	int err = 0;
 296
 297	lockdep_assert_held(&devfreq_list_lock);
 298
 299	if (IS_ERR_OR_NULL(name)) {
 300		pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
 301		return ERR_PTR(-EINVAL);
 302	}
 303
 304	governor = find_devfreq_governor(name);
 305	if (IS_ERR(governor)) {
 306		mutex_unlock(&devfreq_list_lock);
 307
 308		if (!strncmp(name, DEVFREQ_GOV_SIMPLE_ONDEMAND,
 309			     DEVFREQ_NAME_LEN))
 310			err = request_module("governor_%s", "simpleondemand");
 311		else
 312			err = request_module("governor_%s", name);
 313		/* Restore previous state before return */
 314		mutex_lock(&devfreq_list_lock);
 315		if (err)
 316			return (err < 0) ? ERR_PTR(err) : ERR_PTR(-EINVAL);
 317
 318		governor = find_devfreq_governor(name);
 319	}
 320
 321	return governor;
 322}
 323
 324static int devfreq_notify_transition(struct devfreq *devfreq,
 325		struct devfreq_freqs *freqs, unsigned int state)
 326{
 327	if (!devfreq)
 328		return -EINVAL;
 329
 330	switch (state) {
 331	case DEVFREQ_PRECHANGE:
 332		srcu_notifier_call_chain(&devfreq->transition_notifier_list,
 333				DEVFREQ_PRECHANGE, freqs);
 334		break;
 335
 336	case DEVFREQ_POSTCHANGE:
 337		srcu_notifier_call_chain(&devfreq->transition_notifier_list,
 338				DEVFREQ_POSTCHANGE, freqs);
 339		break;
 340	default:
 341		return -EINVAL;
 342	}
 343
 344	return 0;
 345}
 346
 347static int devfreq_set_target(struct devfreq *devfreq, unsigned long new_freq,
 348			      u32 flags)
 349{
 350	struct devfreq_freqs freqs;
 351	unsigned long cur_freq;
 352	int err = 0;
 353
 354	if (devfreq->profile->get_cur_freq)
 355		devfreq->profile->get_cur_freq(devfreq->dev.parent, &cur_freq);
 356	else
 357		cur_freq = devfreq->previous_freq;
 358
 359	freqs.old = cur_freq;
 360	freqs.new = new_freq;
 361	devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE);
 362
 363	err = devfreq->profile->target(devfreq->dev.parent, &new_freq, flags);
 364	if (err) {
 365		freqs.new = cur_freq;
 366		devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
 367		return err;
 368	}
 369
 370	/*
 371	 * Print devfreq_frequency trace information between DEVFREQ_PRECHANGE
 372	 * and DEVFREQ_POSTCHANGE because for showing the correct frequency
 373	 * change order of between devfreq device and passive devfreq device.
 374	 */
 375	if (trace_devfreq_frequency_enabled() && new_freq != cur_freq)
 376		trace_devfreq_frequency(devfreq, new_freq, cur_freq);
 377
 378	freqs.new = new_freq;
 379	devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
 380
 381	if (devfreq_update_status(devfreq, new_freq))
 382		dev_warn(&devfreq->dev,
 383			 "Couldn't update frequency transition information.\n");
 384
 385	devfreq->previous_freq = new_freq;
 386
 387	if (devfreq->suspend_freq)
 388		devfreq->resume_freq = new_freq;
 389
 390	return err;
 391}
 392
 393/**
 394 * devfreq_update_target() - Reevaluate the device and configure frequency
 395 *			   on the final stage.
 396 * @devfreq:	the devfreq instance.
 397 * @freq:	the new frequency of parent device. This argument
 398 *		is only used for devfreq device using passive governor.
 399 *
 400 * Note: Lock devfreq->lock before calling devfreq_update_target. This function
 401 *	 should be only used by both update_devfreq() and devfreq governors.
 402 */
 403int devfreq_update_target(struct devfreq *devfreq, unsigned long freq)
 404{
 405	unsigned long min_freq, max_freq;
 406	int err = 0;
 407	u32 flags = 0;
 408
 409	lockdep_assert_held(&devfreq->lock);
 410
 411	if (!devfreq->governor)
 412		return -EINVAL;
 413
 414	/* Reevaluate the proper frequency */
 415	err = devfreq->governor->get_target_freq(devfreq, &freq);
 416	if (err)
 417		return err;
 418	devfreq_get_freq_range(devfreq, &min_freq, &max_freq);
 419
 420	if (freq < min_freq) {
 421		freq = min_freq;
 422		flags &= ~DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use GLB */
 423	}
 424	if (freq > max_freq) {
 425		freq = max_freq;
 426		flags |= DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use LUB */
 427	}
 428
 429	return devfreq_set_target(devfreq, freq, flags);
 430}
 431EXPORT_SYMBOL(devfreq_update_target);
 432
 433/* Load monitoring helper functions for governors use */
 434
 435/**
 436 * update_devfreq() - Reevaluate the device and configure frequency.
 437 * @devfreq:	the devfreq instance.
 438 *
 439 * Note: Lock devfreq->lock before calling update_devfreq
 440 *	 This function is exported for governors.
 441 */
 442int update_devfreq(struct devfreq *devfreq)
 443{
 444	return devfreq_update_target(devfreq, 0L);
 445}
 446EXPORT_SYMBOL(update_devfreq);
 447
 448/**
 449 * devfreq_monitor() - Periodically poll devfreq objects.
 450 * @work:	the work struct used to run devfreq_monitor periodically.
 451 *
 452 */
 453static void devfreq_monitor(struct work_struct *work)
 454{
 455	int err;
 456	struct devfreq *devfreq = container_of(work,
 457					struct devfreq, work.work);
 458
 459	mutex_lock(&devfreq->lock);
 460	err = update_devfreq(devfreq);
 461	if (err)
 462		dev_err(&devfreq->dev, "dvfs failed with (%d) error\n", err);
 463
 464	queue_delayed_work(devfreq_wq, &devfreq->work,
 465				msecs_to_jiffies(devfreq->profile->polling_ms));
 466	mutex_unlock(&devfreq->lock);
 467
 468	trace_devfreq_monitor(devfreq);
 469}
 470
 471/**
 472 * devfreq_monitor_start() - Start load monitoring of devfreq instance
 473 * @devfreq:	the devfreq instance.
 474 *
 475 * Helper function for starting devfreq device load monitoring. By
 476 * default delayed work based monitoring is supported. Function
 477 * to be called from governor in response to DEVFREQ_GOV_START
 478 * event when device is added to devfreq framework.
 479 */
 480void devfreq_monitor_start(struct devfreq *devfreq)
 481{
 482	if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))
 483		return;
 484
 485	switch (devfreq->profile->timer) {
 486	case DEVFREQ_TIMER_DEFERRABLE:
 487		INIT_DEFERRABLE_WORK(&devfreq->work, devfreq_monitor);
 488		break;
 489	case DEVFREQ_TIMER_DELAYED:
 490		INIT_DELAYED_WORK(&devfreq->work, devfreq_monitor);
 491		break;
 492	default:
 493		return;
 494	}
 495
 496	if (devfreq->profile->polling_ms)
 497		queue_delayed_work(devfreq_wq, &devfreq->work,
 498			msecs_to_jiffies(devfreq->profile->polling_ms));
 499}
 500EXPORT_SYMBOL(devfreq_monitor_start);
 501
 502/**
 503 * devfreq_monitor_stop() - Stop load monitoring of a devfreq instance
 504 * @devfreq:	the devfreq instance.
 505 *
 506 * Helper function to stop devfreq device load monitoring. Function
 507 * to be called from governor in response to DEVFREQ_GOV_STOP
 508 * event when device is removed from devfreq framework.
 509 */
 510void devfreq_monitor_stop(struct devfreq *devfreq)
 511{
 512	if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))
 513		return;
 514
 515	cancel_delayed_work_sync(&devfreq->work);
 516}
 517EXPORT_SYMBOL(devfreq_monitor_stop);
 518
 519/**
 520 * devfreq_monitor_suspend() - Suspend load monitoring of a devfreq instance
 521 * @devfreq:	the devfreq instance.
 522 *
 523 * Helper function to suspend devfreq device load monitoring. Function
 524 * to be called from governor in response to DEVFREQ_GOV_SUSPEND
 525 * event or when polling interval is set to zero.
 526 *
 527 * Note: Though this function is same as devfreq_monitor_stop(),
 528 * intentionally kept separate to provide hooks for collecting
 529 * transition statistics.
 530 */
 531void devfreq_monitor_suspend(struct devfreq *devfreq)
 532{
 533	mutex_lock(&devfreq->lock);
 534	if (devfreq->stop_polling) {
 535		mutex_unlock(&devfreq->lock);
 536		return;
 537	}
 538
 539	devfreq_update_status(devfreq, devfreq->previous_freq);
 540	devfreq->stop_polling = true;
 541	mutex_unlock(&devfreq->lock);
 542
 543	if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))
 544		return;
 545
 546	cancel_delayed_work_sync(&devfreq->work);
 547}
 548EXPORT_SYMBOL(devfreq_monitor_suspend);
 549
 550/**
 551 * devfreq_monitor_resume() - Resume load monitoring of a devfreq instance
 552 * @devfreq:    the devfreq instance.
 553 *
 554 * Helper function to resume devfreq device load monitoring. Function
 555 * to be called from governor in response to DEVFREQ_GOV_RESUME
 556 * event or when polling interval is set to non-zero.
 557 */
 558void devfreq_monitor_resume(struct devfreq *devfreq)
 559{
 560	unsigned long freq;
 561
 562	mutex_lock(&devfreq->lock);
 563
 564	if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))
 565		goto out_update;
 566
 567	if (!devfreq->stop_polling)
 568		goto out;
 569
 570	if (!delayed_work_pending(&devfreq->work) &&
 571			devfreq->profile->polling_ms)
 572		queue_delayed_work(devfreq_wq, &devfreq->work,
 573			msecs_to_jiffies(devfreq->profile->polling_ms));
 574
 575out_update:
 576	devfreq->stats.last_update = get_jiffies_64();
 577	devfreq->stop_polling = false;
 578
 579	if (devfreq->profile->get_cur_freq &&
 580		!devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
 581		devfreq->previous_freq = freq;
 582
 583out:
 584	mutex_unlock(&devfreq->lock);
 585}
 586EXPORT_SYMBOL(devfreq_monitor_resume);
 587
 588/**
 589 * devfreq_update_interval() - Update device devfreq monitoring interval
 590 * @devfreq:    the devfreq instance.
 591 * @delay:      new polling interval to be set.
 592 *
 593 * Helper function to set new load monitoring polling interval. Function
 594 * to be called from governor in response to DEVFREQ_GOV_UPDATE_INTERVAL event.
 595 */
 596void devfreq_update_interval(struct devfreq *devfreq, unsigned int *delay)
 597{
 598	unsigned int cur_delay = devfreq->profile->polling_ms;
 599	unsigned int new_delay = *delay;
 600
 601	mutex_lock(&devfreq->lock);
 602	devfreq->profile->polling_ms = new_delay;
 603
 604	if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))
 605		goto out;
 606
 607	if (devfreq->stop_polling)
 608		goto out;
 609
 610	/* if new delay is zero, stop polling */
 611	if (!new_delay) {
 612		mutex_unlock(&devfreq->lock);
 613		cancel_delayed_work_sync(&devfreq->work);
 614		return;
 615	}
 616
 617	/* if current delay is zero, start polling with new delay */
 618	if (!cur_delay) {
 619		queue_delayed_work(devfreq_wq, &devfreq->work,
 620			msecs_to_jiffies(devfreq->profile->polling_ms));
 621		goto out;
 622	}
 623
 624	/* if current delay is greater than new delay, restart polling */
 625	if (cur_delay > new_delay) {
 626		mutex_unlock(&devfreq->lock);
 627		cancel_delayed_work_sync(&devfreq->work);
 628		mutex_lock(&devfreq->lock);
 629		if (!devfreq->stop_polling)
 630			queue_delayed_work(devfreq_wq, &devfreq->work,
 631				msecs_to_jiffies(devfreq->profile->polling_ms));
 632	}
 633out:
 634	mutex_unlock(&devfreq->lock);
 635}
 636EXPORT_SYMBOL(devfreq_update_interval);
 637
 638/**
 639 * devfreq_notifier_call() - Notify that the device frequency requirements
 640 *			     has been changed out of devfreq framework.
 641 * @nb:		the notifier_block (supposed to be devfreq->nb)
 642 * @type:	not used
 643 * @devp:	not used
 644 *
 645 * Called by a notifier that uses devfreq->nb.
 646 */
 647static int devfreq_notifier_call(struct notifier_block *nb, unsigned long type,
 648				 void *devp)
 649{
 650	struct devfreq *devfreq = container_of(nb, struct devfreq, nb);
 651	int err = -EINVAL;
 652
 653	mutex_lock(&devfreq->lock);
 654
 655	devfreq->scaling_min_freq = find_available_min_freq(devfreq);
 656	if (!devfreq->scaling_min_freq)
 657		goto out;
 658
 659	devfreq->scaling_max_freq = find_available_max_freq(devfreq);
 660	if (!devfreq->scaling_max_freq) {
 661		devfreq->scaling_max_freq = ULONG_MAX;
 662		goto out;
 663	}
 664
 665	err = update_devfreq(devfreq);
 666
 667out:
 668	mutex_unlock(&devfreq->lock);
 669	if (err)
 670		dev_err(devfreq->dev.parent,
 671			"failed to update frequency from OPP notifier (%d)\n",
 672			err);
 673
 674	return NOTIFY_OK;
 675}
 676
 677/**
 678 * qos_notifier_call() - Common handler for QoS constraints.
 679 * @devfreq:    the devfreq instance.
 680 */
 681static int qos_notifier_call(struct devfreq *devfreq)
 682{
 683	int err;
 684
 685	mutex_lock(&devfreq->lock);
 686	err = update_devfreq(devfreq);
 687	mutex_unlock(&devfreq->lock);
 688	if (err)
 689		dev_err(devfreq->dev.parent,
 690			"failed to update frequency from PM QoS (%d)\n",
 691			err);
 692
 693	return NOTIFY_OK;
 694}
 695
 696/**
 697 * qos_min_notifier_call() - Callback for QoS min_freq changes.
 698 * @nb:		Should be devfreq->nb_min
 699 * @val:	not used
 700 * @ptr:	not used
 701 */
 702static int qos_min_notifier_call(struct notifier_block *nb,
 703					 unsigned long val, void *ptr)
 704{
 705	return qos_notifier_call(container_of(nb, struct devfreq, nb_min));
 706}
 707
 708/**
 709 * qos_max_notifier_call() - Callback for QoS max_freq changes.
 710 * @nb:		Should be devfreq->nb_max
 711 * @val:	not used
 712 * @ptr:	not used
 713 */
 714static int qos_max_notifier_call(struct notifier_block *nb,
 715					 unsigned long val, void *ptr)
 716{
 717	return qos_notifier_call(container_of(nb, struct devfreq, nb_max));
 718}
 719
 720/**
 721 * devfreq_dev_release() - Callback for struct device to release the device.
 722 * @dev:	the devfreq device
 723 *
 724 * Remove devfreq from the list and release its resources.
 725 */
 726static void devfreq_dev_release(struct device *dev)
 727{
 728	struct devfreq *devfreq = to_devfreq(dev);
 729	int err;
 730
 731	mutex_lock(&devfreq_list_lock);
 732	list_del(&devfreq->node);
 733	mutex_unlock(&devfreq_list_lock);
 734
 735	err = dev_pm_qos_remove_notifier(devfreq->dev.parent, &devfreq->nb_max,
 736					 DEV_PM_QOS_MAX_FREQUENCY);
 737	if (err && err != -ENOENT)
 738		dev_warn(dev->parent,
 739			"Failed to remove max_freq notifier: %d\n", err);
 740	err = dev_pm_qos_remove_notifier(devfreq->dev.parent, &devfreq->nb_min,
 741					 DEV_PM_QOS_MIN_FREQUENCY);
 742	if (err && err != -ENOENT)
 743		dev_warn(dev->parent,
 744			"Failed to remove min_freq notifier: %d\n", err);
 745
 746	if (dev_pm_qos_request_active(&devfreq->user_max_freq_req)) {
 747		err = dev_pm_qos_remove_request(&devfreq->user_max_freq_req);
 748		if (err < 0)
 749			dev_warn(dev->parent,
 750				"Failed to remove max_freq request: %d\n", err);
 751	}
 752	if (dev_pm_qos_request_active(&devfreq->user_min_freq_req)) {
 753		err = dev_pm_qos_remove_request(&devfreq->user_min_freq_req);
 754		if (err < 0)
 755			dev_warn(dev->parent,
 756				"Failed to remove min_freq request: %d\n", err);
 757	}
 758
 759	if (devfreq->profile->exit)
 760		devfreq->profile->exit(devfreq->dev.parent);
 761
 762	if (devfreq->opp_table)
 763		dev_pm_opp_put_opp_table(devfreq->opp_table);
 764
 765	mutex_destroy(&devfreq->lock);
 766	kfree(devfreq);
 767}
 768
 769static void create_sysfs_files(struct devfreq *devfreq,
 770				const struct devfreq_governor *gov);
 771static void remove_sysfs_files(struct devfreq *devfreq,
 772				const struct devfreq_governor *gov);
 773
 774/**
 775 * devfreq_add_device() - Add devfreq feature to the device
 776 * @dev:	the device to add devfreq feature.
 777 * @profile:	device-specific profile to run devfreq.
 778 * @governor_name:	name of the policy to choose frequency.
 779 * @data:	devfreq driver pass to governors, governor should not change it.
 
 780 */
 781struct devfreq *devfreq_add_device(struct device *dev,
 782				   struct devfreq_dev_profile *profile,
 783				   const char *governor_name,
 784				   void *data)
 785{
 786	struct devfreq *devfreq;
 787	struct devfreq_governor *governor;
 788	unsigned long min_freq, max_freq;
 789	int err = 0;
 790
 791	if (!dev || !profile || !governor_name) {
 792		dev_err(dev, "%s: Invalid parameters.\n", __func__);
 793		return ERR_PTR(-EINVAL);
 794	}
 795
 796	mutex_lock(&devfreq_list_lock);
 797	devfreq = find_device_devfreq(dev);
 798	mutex_unlock(&devfreq_list_lock);
 799	if (!IS_ERR(devfreq)) {
 800		dev_err(dev, "%s: devfreq device already exists!\n",
 801			__func__);
 802		err = -EINVAL;
 803		goto err_out;
 804	}
 805
 806	devfreq = kzalloc(sizeof(struct devfreq), GFP_KERNEL);
 807	if (!devfreq) {
 808		err = -ENOMEM;
 809		goto err_out;
 810	}
 811
 812	mutex_init(&devfreq->lock);
 813	mutex_lock(&devfreq->lock);
 814	devfreq->dev.parent = dev;
 815	devfreq->dev.class = devfreq_class;
 816	devfreq->dev.release = devfreq_dev_release;
 817	INIT_LIST_HEAD(&devfreq->node);
 818	devfreq->profile = profile;
 819	devfreq->previous_freq = profile->initial_freq;
 820	devfreq->last_status.current_frequency = profile->initial_freq;
 821	devfreq->data = data;
 822	devfreq->nb.notifier_call = devfreq_notifier_call;
 823
 824	if (devfreq->profile->timer < 0
 825		|| devfreq->profile->timer >= DEVFREQ_TIMER_NUM) {
 826		mutex_unlock(&devfreq->lock);
 827		err = -EINVAL;
 828		goto err_dev;
 829	}
 830
 831	if (!devfreq->profile->max_state || !devfreq->profile->freq_table) {
 832		mutex_unlock(&devfreq->lock);
 833		err = set_freq_table(devfreq);
 834		if (err < 0)
 835			goto err_dev;
 836		mutex_lock(&devfreq->lock);
 837	} else {
 838		devfreq->freq_table = devfreq->profile->freq_table;
 839		devfreq->max_state = devfreq->profile->max_state;
 840	}
 841
 842	devfreq->scaling_min_freq = find_available_min_freq(devfreq);
 843	if (!devfreq->scaling_min_freq) {
 844		mutex_unlock(&devfreq->lock);
 845		err = -EINVAL;
 846		goto err_dev;
 847	}
 848
 849	devfreq->scaling_max_freq = find_available_max_freq(devfreq);
 850	if (!devfreq->scaling_max_freq) {
 851		mutex_unlock(&devfreq->lock);
 852		err = -EINVAL;
 853		goto err_dev;
 854	}
 855
 856	devfreq_get_freq_range(devfreq, &min_freq, &max_freq);
 857
 858	devfreq->suspend_freq = dev_pm_opp_get_suspend_opp_freq(dev);
 859	devfreq->opp_table = dev_pm_opp_get_opp_table(dev);
 860	if (IS_ERR(devfreq->opp_table))
 861		devfreq->opp_table = NULL;
 862
 863	atomic_set(&devfreq->suspend_count, 0);
 864
 865	dev_set_name(&devfreq->dev, "%s", dev_name(dev));
 866	err = device_register(&devfreq->dev);
 867	if (err) {
 868		mutex_unlock(&devfreq->lock);
 869		put_device(&devfreq->dev);
 870		goto err_out;
 871	}
 872
 873	devfreq->stats.trans_table = devm_kzalloc(&devfreq->dev,
 874			array3_size(sizeof(unsigned int),
 875				    devfreq->max_state,
 876				    devfreq->max_state),
 877			GFP_KERNEL);
 878	if (!devfreq->stats.trans_table) {
 879		mutex_unlock(&devfreq->lock);
 880		err = -ENOMEM;
 881		goto err_devfreq;
 882	}
 883
 884	devfreq->stats.time_in_state = devm_kcalloc(&devfreq->dev,
 885			devfreq->max_state,
 886			sizeof(*devfreq->stats.time_in_state),
 887			GFP_KERNEL);
 888	if (!devfreq->stats.time_in_state) {
 889		mutex_unlock(&devfreq->lock);
 890		err = -ENOMEM;
 891		goto err_devfreq;
 892	}
 893
 894	devfreq->stats.total_trans = 0;
 895	devfreq->stats.last_update = get_jiffies_64();
 896
 897	srcu_init_notifier_head(&devfreq->transition_notifier_list);
 898
 899	mutex_unlock(&devfreq->lock);
 900
 901	err = dev_pm_qos_add_request(dev, &devfreq->user_min_freq_req,
 902				     DEV_PM_QOS_MIN_FREQUENCY, 0);
 903	if (err < 0)
 904		goto err_devfreq;
 905	err = dev_pm_qos_add_request(dev, &devfreq->user_max_freq_req,
 906				     DEV_PM_QOS_MAX_FREQUENCY,
 907				     PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE);
 908	if (err < 0)
 909		goto err_devfreq;
 910
 911	devfreq->nb_min.notifier_call = qos_min_notifier_call;
 912	err = dev_pm_qos_add_notifier(dev, &devfreq->nb_min,
 913				      DEV_PM_QOS_MIN_FREQUENCY);
 914	if (err)
 915		goto err_devfreq;
 916
 917	devfreq->nb_max.notifier_call = qos_max_notifier_call;
 918	err = dev_pm_qos_add_notifier(dev, &devfreq->nb_max,
 919				      DEV_PM_QOS_MAX_FREQUENCY);
 920	if (err)
 921		goto err_devfreq;
 922
 923	mutex_lock(&devfreq_list_lock);
 924
 925	governor = try_then_request_governor(governor_name);
 926	if (IS_ERR(governor)) {
 927		dev_err(dev, "%s: Unable to find governor for the device\n",
 928			__func__);
 929		err = PTR_ERR(governor);
 930		goto err_init;
 931	}
 932
 933	devfreq->governor = governor;
 934	err = devfreq->governor->event_handler(devfreq, DEVFREQ_GOV_START,
 935						NULL);
 936	if (err) {
 937		dev_err_probe(dev, err,
 938			"%s: Unable to start governor for the device\n",
 939			 __func__);
 940		goto err_init;
 941	}
 942	create_sysfs_files(devfreq, devfreq->governor);
 943
 944	list_add(&devfreq->node, &devfreq_list);
 945
 946	mutex_unlock(&devfreq_list_lock);
 947
 948	if (devfreq->profile->is_cooling_device) {
 949		devfreq->cdev = devfreq_cooling_em_register(devfreq, NULL);
 950		if (IS_ERR(devfreq->cdev))
 951			devfreq->cdev = NULL;
 952	}
 953
 954	return devfreq;
 955
 956err_init:
 957	mutex_unlock(&devfreq_list_lock);
 958err_devfreq:
 959	devfreq_remove_device(devfreq);
 960	devfreq = NULL;
 961err_dev:
 962	kfree(devfreq);
 963err_out:
 964	return ERR_PTR(err);
 965}
 966EXPORT_SYMBOL(devfreq_add_device);
 967
 968/**
 969 * devfreq_remove_device() - Remove devfreq feature from a device.
 970 * @devfreq:	the devfreq instance to be removed
 971 *
 972 * The opposite of devfreq_add_device().
 973 */
 974int devfreq_remove_device(struct devfreq *devfreq)
 975{
 976	if (!devfreq)
 977		return -EINVAL;
 978
 979	devfreq_cooling_unregister(devfreq->cdev);
 980
 981	if (devfreq->governor) {
 982		devfreq->governor->event_handler(devfreq,
 983						 DEVFREQ_GOV_STOP, NULL);
 984		remove_sysfs_files(devfreq, devfreq->governor);
 985	}
 986
 987	device_unregister(&devfreq->dev);
 988
 989	return 0;
 990}
 991EXPORT_SYMBOL(devfreq_remove_device);
 992
 993static int devm_devfreq_dev_match(struct device *dev, void *res, void *data)
 994{
 995	struct devfreq **r = res;
 996
 997	if (WARN_ON(!r || !*r))
 998		return 0;
 999
1000	return *r == data;
1001}
1002
1003static void devm_devfreq_dev_release(struct device *dev, void *res)
1004{
1005	devfreq_remove_device(*(struct devfreq **)res);
1006}
1007
1008/**
1009 * devm_devfreq_add_device() - Resource-managed devfreq_add_device()
1010 * @dev:	the device to add devfreq feature.
1011 * @profile:	device-specific profile to run devfreq.
1012 * @governor_name:	name of the policy to choose frequency.
1013 * @data:	 devfreq driver pass to governors, governor should not change it.
 
1014 *
1015 * This function manages automatically the memory of devfreq device using device
1016 * resource management and simplify the free operation for memory of devfreq
1017 * device.
1018 */
1019struct devfreq *devm_devfreq_add_device(struct device *dev,
1020					struct devfreq_dev_profile *profile,
1021					const char *governor_name,
1022					void *data)
1023{
1024	struct devfreq **ptr, *devfreq;
1025
1026	ptr = devres_alloc(devm_devfreq_dev_release, sizeof(*ptr), GFP_KERNEL);
1027	if (!ptr)
1028		return ERR_PTR(-ENOMEM);
1029
1030	devfreq = devfreq_add_device(dev, profile, governor_name, data);
1031	if (IS_ERR(devfreq)) {
1032		devres_free(ptr);
1033		return devfreq;
1034	}
1035
1036	*ptr = devfreq;
1037	devres_add(dev, ptr);
1038
1039	return devfreq;
1040}
1041EXPORT_SYMBOL(devm_devfreq_add_device);
1042
1043#ifdef CONFIG_OF
1044/*
1045 * devfreq_get_devfreq_by_node - Get the devfreq device from devicetree
1046 * @node - pointer to device_node
1047 *
1048 * return the instance of devfreq device
1049 */
1050struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node)
1051{
1052	struct devfreq *devfreq;
1053
1054	if (!node)
1055		return ERR_PTR(-EINVAL);
1056
1057	mutex_lock(&devfreq_list_lock);
1058	list_for_each_entry(devfreq, &devfreq_list, node) {
1059		if (devfreq->dev.parent
1060			&& device_match_of_node(devfreq->dev.parent, node)) {
1061			mutex_unlock(&devfreq_list_lock);
1062			return devfreq;
1063		}
1064	}
1065	mutex_unlock(&devfreq_list_lock);
1066
1067	return ERR_PTR(-ENODEV);
1068}
1069
1070/*
1071 * devfreq_get_devfreq_by_phandle - Get the devfreq device from devicetree
1072 * @dev - instance to the given device
1073 * @phandle_name - name of property holding a phandle value
1074 * @index - index into list of devfreq
1075 *
1076 * return the instance of devfreq device
1077 */
1078struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
1079					const char *phandle_name, int index)
1080{
1081	struct device_node *node;
1082	struct devfreq *devfreq;
1083
1084	if (!dev || !phandle_name)
1085		return ERR_PTR(-EINVAL);
1086
1087	if (!dev->of_node)
1088		return ERR_PTR(-EINVAL);
1089
1090	node = of_parse_phandle(dev->of_node, phandle_name, index);
1091	if (!node)
1092		return ERR_PTR(-ENODEV);
1093
1094	devfreq = devfreq_get_devfreq_by_node(node);
1095	of_node_put(node);
1096
1097	return devfreq;
1098}
1099
1100#else
1101struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node)
1102{
1103	return ERR_PTR(-ENODEV);
1104}
1105
1106struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
1107					const char *phandle_name, int index)
1108{
1109	return ERR_PTR(-ENODEV);
1110}
1111#endif /* CONFIG_OF */
1112EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_node);
1113EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_phandle);
1114
1115/**
1116 * devm_devfreq_remove_device() - Resource-managed devfreq_remove_device()
1117 * @dev:	the device from which to remove devfreq feature.
1118 * @devfreq:	the devfreq instance to be removed
1119 */
1120void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq)
1121{
1122	WARN_ON(devres_release(dev, devm_devfreq_dev_release,
1123			       devm_devfreq_dev_match, devfreq));
1124}
1125EXPORT_SYMBOL(devm_devfreq_remove_device);
1126
1127/**
1128 * devfreq_suspend_device() - Suspend devfreq of a device.
1129 * @devfreq: the devfreq instance to be suspended
1130 *
1131 * This function is intended to be called by the pm callbacks
1132 * (e.g., runtime_suspend, suspend) of the device driver that
1133 * holds the devfreq.
1134 */
1135int devfreq_suspend_device(struct devfreq *devfreq)
1136{
1137	int ret;
1138
1139	if (!devfreq)
1140		return -EINVAL;
1141
1142	if (atomic_inc_return(&devfreq->suspend_count) > 1)
1143		return 0;
1144
1145	if (devfreq->governor) {
1146		ret = devfreq->governor->event_handler(devfreq,
1147					DEVFREQ_GOV_SUSPEND, NULL);
1148		if (ret)
1149			return ret;
1150	}
1151
1152	if (devfreq->suspend_freq) {
1153		mutex_lock(&devfreq->lock);
1154		ret = devfreq_set_target(devfreq, devfreq->suspend_freq, 0);
1155		mutex_unlock(&devfreq->lock);
1156		if (ret)
1157			return ret;
1158	}
1159
1160	return 0;
1161}
1162EXPORT_SYMBOL(devfreq_suspend_device);
1163
1164/**
1165 * devfreq_resume_device() - Resume devfreq of a device.
1166 * @devfreq: the devfreq instance to be resumed
1167 *
1168 * This function is intended to be called by the pm callbacks
1169 * (e.g., runtime_resume, resume) of the device driver that
1170 * holds the devfreq.
1171 */
1172int devfreq_resume_device(struct devfreq *devfreq)
1173{
1174	int ret;
1175
1176	if (!devfreq)
1177		return -EINVAL;
1178
1179	if (atomic_dec_return(&devfreq->suspend_count) >= 1)
1180		return 0;
1181
1182	if (devfreq->resume_freq) {
1183		mutex_lock(&devfreq->lock);
1184		ret = devfreq_set_target(devfreq, devfreq->resume_freq, 0);
1185		mutex_unlock(&devfreq->lock);
1186		if (ret)
1187			return ret;
1188	}
1189
1190	if (devfreq->governor) {
1191		ret = devfreq->governor->event_handler(devfreq,
1192					DEVFREQ_GOV_RESUME, NULL);
1193		if (ret)
1194			return ret;
1195	}
1196
1197	return 0;
1198}
1199EXPORT_SYMBOL(devfreq_resume_device);
1200
1201/**
1202 * devfreq_suspend() - Suspend devfreq governors and devices
1203 *
1204 * Called during system wide Suspend/Hibernate cycles for suspending governors
1205 * and devices preserving the state for resume. On some platforms the devfreq
1206 * device must have precise state (frequency) after resume in order to provide
1207 * fully operating setup.
1208 */
1209void devfreq_suspend(void)
1210{
1211	struct devfreq *devfreq;
1212	int ret;
1213
1214	mutex_lock(&devfreq_list_lock);
1215	list_for_each_entry(devfreq, &devfreq_list, node) {
1216		ret = devfreq_suspend_device(devfreq);
1217		if (ret)
1218			dev_err(&devfreq->dev,
1219				"failed to suspend devfreq device\n");
1220	}
1221	mutex_unlock(&devfreq_list_lock);
1222}
1223
1224/**
1225 * devfreq_resume() - Resume devfreq governors and devices
1226 *
1227 * Called during system wide Suspend/Hibernate cycle for resuming governors and
1228 * devices that are suspended with devfreq_suspend().
1229 */
1230void devfreq_resume(void)
1231{
1232	struct devfreq *devfreq;
1233	int ret;
1234
1235	mutex_lock(&devfreq_list_lock);
1236	list_for_each_entry(devfreq, &devfreq_list, node) {
1237		ret = devfreq_resume_device(devfreq);
1238		if (ret)
1239			dev_warn(&devfreq->dev,
1240				 "failed to resume devfreq device\n");
1241	}
1242	mutex_unlock(&devfreq_list_lock);
1243}
1244
1245/**
1246 * devfreq_add_governor() - Add devfreq governor
1247 * @governor:	the devfreq governor to be added
1248 */
1249int devfreq_add_governor(struct devfreq_governor *governor)
1250{
1251	struct devfreq_governor *g;
1252	struct devfreq *devfreq;
1253	int err = 0;
1254
1255	if (!governor) {
1256		pr_err("%s: Invalid parameters.\n", __func__);
1257		return -EINVAL;
1258	}
1259
1260	mutex_lock(&devfreq_list_lock);
1261	g = find_devfreq_governor(governor->name);
1262	if (!IS_ERR(g)) {
1263		pr_err("%s: governor %s already registered\n", __func__,
1264		       g->name);
1265		err = -EINVAL;
1266		goto err_out;
1267	}
1268
1269	list_add(&governor->node, &devfreq_governor_list);
1270
1271	list_for_each_entry(devfreq, &devfreq_list, node) {
1272		int ret = 0;
1273		struct device *dev = devfreq->dev.parent;
1274
1275		if (!strncmp(devfreq->governor->name, governor->name,
1276			     DEVFREQ_NAME_LEN)) {
1277			/* The following should never occur */
1278			if (devfreq->governor) {
1279				dev_warn(dev,
1280					 "%s: Governor %s already present\n",
1281					 __func__, devfreq->governor->name);
1282				ret = devfreq->governor->event_handler(devfreq,
1283							DEVFREQ_GOV_STOP, NULL);
1284				if (ret) {
1285					dev_warn(dev,
1286						 "%s: Governor %s stop = %d\n",
1287						 __func__,
1288						 devfreq->governor->name, ret);
1289				}
1290				/* Fall through */
1291			}
1292			devfreq->governor = governor;
1293			ret = devfreq->governor->event_handler(devfreq,
1294						DEVFREQ_GOV_START, NULL);
1295			if (ret) {
1296				dev_warn(dev, "%s: Governor %s start=%d\n",
1297					 __func__, devfreq->governor->name,
1298					 ret);
1299			}
1300		}
1301	}
1302
1303err_out:
1304	mutex_unlock(&devfreq_list_lock);
1305
1306	return err;
1307}
1308EXPORT_SYMBOL(devfreq_add_governor);
1309
1310static void devm_devfreq_remove_governor(void *governor)
1311{
1312	WARN_ON(devfreq_remove_governor(governor));
1313}
1314
1315/**
1316 * devm_devfreq_add_governor() - Add devfreq governor
1317 * @dev:	device which adds devfreq governor
1318 * @governor:	the devfreq governor to be added
1319 *
1320 * This is a resource-managed variant of devfreq_add_governor().
1321 */
1322int devm_devfreq_add_governor(struct device *dev,
1323			      struct devfreq_governor *governor)
1324{
1325	int err;
1326
1327	err = devfreq_add_governor(governor);
1328	if (err)
1329		return err;
1330
1331	return devm_add_action_or_reset(dev, devm_devfreq_remove_governor,
1332					governor);
1333}
1334EXPORT_SYMBOL(devm_devfreq_add_governor);
1335
1336/**
1337 * devfreq_remove_governor() - Remove devfreq feature from a device.
1338 * @governor:	the devfreq governor to be removed
1339 */
1340int devfreq_remove_governor(struct devfreq_governor *governor)
1341{
1342	struct devfreq_governor *g;
1343	struct devfreq *devfreq;
1344	int err = 0;
1345
1346	if (!governor) {
1347		pr_err("%s: Invalid parameters.\n", __func__);
1348		return -EINVAL;
1349	}
1350
1351	mutex_lock(&devfreq_list_lock);
1352	g = find_devfreq_governor(governor->name);
1353	if (IS_ERR(g)) {
1354		pr_err("%s: governor %s not registered\n", __func__,
1355		       governor->name);
1356		err = PTR_ERR(g);
1357		goto err_out;
1358	}
1359	list_for_each_entry(devfreq, &devfreq_list, node) {
1360		int ret;
1361		struct device *dev = devfreq->dev.parent;
1362
1363		if (!strncmp(devfreq->governor->name, governor->name,
1364			     DEVFREQ_NAME_LEN)) {
1365			/* we should have a devfreq governor! */
1366			if (!devfreq->governor) {
1367				dev_warn(dev, "%s: Governor %s NOT present\n",
1368					 __func__, governor->name);
1369				continue;
1370				/* Fall through */
1371			}
1372			ret = devfreq->governor->event_handler(devfreq,
1373						DEVFREQ_GOV_STOP, NULL);
1374			if (ret) {
1375				dev_warn(dev, "%s: Governor %s stop=%d\n",
1376					 __func__, devfreq->governor->name,
1377					 ret);
1378			}
1379			devfreq->governor = NULL;
1380		}
1381	}
1382
1383	list_del(&governor->node);
1384err_out:
1385	mutex_unlock(&devfreq_list_lock);
1386
1387	return err;
1388}
1389EXPORT_SYMBOL(devfreq_remove_governor);
1390
1391static ssize_t name_show(struct device *dev,
1392			struct device_attribute *attr, char *buf)
1393{
1394	struct devfreq *df = to_devfreq(dev);
1395	return sprintf(buf, "%s\n", dev_name(df->dev.parent));
1396}
1397static DEVICE_ATTR_RO(name);
1398
1399static ssize_t governor_show(struct device *dev,
1400			     struct device_attribute *attr, char *buf)
1401{
1402	struct devfreq *df = to_devfreq(dev);
1403
1404	if (!df->governor)
1405		return -EINVAL;
1406
1407	return sprintf(buf, "%s\n", df->governor->name);
1408}
1409
1410static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
1411			      const char *buf, size_t count)
1412{
1413	struct devfreq *df = to_devfreq(dev);
1414	int ret;
1415	char str_governor[DEVFREQ_NAME_LEN + 1];
1416	const struct devfreq_governor *governor, *prev_governor;
1417
1418	if (!df->governor)
1419		return -EINVAL;
1420
1421	ret = sscanf(buf, "%" __stringify(DEVFREQ_NAME_LEN) "s", str_governor);
1422	if (ret != 1)
1423		return -EINVAL;
1424
1425	mutex_lock(&devfreq_list_lock);
1426	governor = try_then_request_governor(str_governor);
1427	if (IS_ERR(governor)) {
1428		ret = PTR_ERR(governor);
1429		goto out;
1430	}
1431	if (df->governor == governor) {
1432		ret = 0;
1433		goto out;
1434	} else if (IS_SUPPORTED_FLAG(df->governor->flags, IMMUTABLE)
1435		|| IS_SUPPORTED_FLAG(governor->flags, IMMUTABLE)) {
1436		ret = -EINVAL;
1437		goto out;
1438	}
1439
1440	/*
1441	 * Stop the current governor and remove the specific sysfs files
1442	 * which depend on current governor.
1443	 */
1444	ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
1445	if (ret) {
1446		dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
1447			 __func__, df->governor->name, ret);
1448		goto out;
1449	}
1450	remove_sysfs_files(df, df->governor);
1451
1452	/*
1453	 * Start the new governor and create the specific sysfs files
1454	 * which depend on the new governor.
1455	 */
1456	prev_governor = df->governor;
1457	df->governor = governor;
1458	ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
1459	if (ret) {
1460		dev_warn(dev, "%s: Governor %s not started(%d)\n",
1461			 __func__, df->governor->name, ret);
1462
1463		/* Restore previous governor */
1464		df->governor = prev_governor;
1465		ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
1466		if (ret) {
1467			dev_err(dev,
1468				"%s: reverting to Governor %s failed (%d)\n",
1469				__func__, prev_governor->name, ret);
1470			df->governor = NULL;
1471			goto out;
1472		}
1473	}
1474
1475	/*
1476	 * Create the sysfs files for the new governor. But if failed to start
1477	 * the new governor, restore the sysfs files of previous governor.
1478	 */
1479	create_sysfs_files(df, df->governor);
1480
1481out:
1482	mutex_unlock(&devfreq_list_lock);
1483
1484	if (!ret)
1485		ret = count;
1486	return ret;
1487}
1488static DEVICE_ATTR_RW(governor);
1489
1490static ssize_t available_governors_show(struct device *d,
1491					struct device_attribute *attr,
1492					char *buf)
1493{
1494	struct devfreq *df = to_devfreq(d);
1495	ssize_t count = 0;
1496
1497	if (!df->governor)
1498		return -EINVAL;
1499
1500	mutex_lock(&devfreq_list_lock);
1501
1502	/*
1503	 * The devfreq with immutable governor (e.g., passive) shows
1504	 * only own governor.
1505	 */
1506	if (IS_SUPPORTED_FLAG(df->governor->flags, IMMUTABLE)) {
1507		count = scnprintf(&buf[count], DEVFREQ_NAME_LEN,
1508				  "%s ", df->governor->name);
1509	/*
1510	 * The devfreq device shows the registered governor except for
1511	 * immutable governors such as passive governor .
1512	 */
1513	} else {
1514		struct devfreq_governor *governor;
1515
1516		list_for_each_entry(governor, &devfreq_governor_list, node) {
1517			if (IS_SUPPORTED_FLAG(governor->flags, IMMUTABLE))
1518				continue;
1519			count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1520					   "%s ", governor->name);
1521		}
1522	}
1523
1524	mutex_unlock(&devfreq_list_lock);
1525
1526	/* Truncate the trailing space */
1527	if (count)
1528		count--;
1529
1530	count += sprintf(&buf[count], "\n");
1531
1532	return count;
1533}
1534static DEVICE_ATTR_RO(available_governors);
1535
1536static ssize_t cur_freq_show(struct device *dev, struct device_attribute *attr,
1537			     char *buf)
1538{
1539	unsigned long freq;
1540	struct devfreq *df = to_devfreq(dev);
1541
1542	if (!df->profile)
1543		return -EINVAL;
1544
1545	if (df->profile->get_cur_freq &&
1546		!df->profile->get_cur_freq(df->dev.parent, &freq))
1547		return sprintf(buf, "%lu\n", freq);
1548
1549	return sprintf(buf, "%lu\n", df->previous_freq);
1550}
1551static DEVICE_ATTR_RO(cur_freq);
1552
1553static ssize_t target_freq_show(struct device *dev,
1554				struct device_attribute *attr, char *buf)
1555{
1556	struct devfreq *df = to_devfreq(dev);
1557
1558	return sprintf(buf, "%lu\n", df->previous_freq);
1559}
1560static DEVICE_ATTR_RO(target_freq);
1561
1562static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
1563			      const char *buf, size_t count)
1564{
1565	struct devfreq *df = to_devfreq(dev);
1566	unsigned long value;
1567	int ret;
1568
1569	/*
1570	 * Protect against theoretical sysfs writes between
1571	 * device_add and dev_pm_qos_add_request
1572	 */
1573	if (!dev_pm_qos_request_active(&df->user_min_freq_req))
1574		return -EAGAIN;
1575
1576	ret = sscanf(buf, "%lu", &value);
1577	if (ret != 1)
1578		return -EINVAL;
1579
1580	/* Round down to kHz for PM QoS */
1581	ret = dev_pm_qos_update_request(&df->user_min_freq_req,
1582					value / HZ_PER_KHZ);
1583	if (ret < 0)
1584		return ret;
1585
1586	return count;
1587}
1588
1589static ssize_t min_freq_show(struct device *dev, struct device_attribute *attr,
1590			     char *buf)
1591{
1592	struct devfreq *df = to_devfreq(dev);
1593	unsigned long min_freq, max_freq;
1594
1595	mutex_lock(&df->lock);
1596	devfreq_get_freq_range(df, &min_freq, &max_freq);
1597	mutex_unlock(&df->lock);
1598
1599	return sprintf(buf, "%lu\n", min_freq);
1600}
1601static DEVICE_ATTR_RW(min_freq);
1602
1603static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
1604			      const char *buf, size_t count)
1605{
1606	struct devfreq *df = to_devfreq(dev);
1607	unsigned long value;
1608	int ret;
1609
1610	/*
1611	 * Protect against theoretical sysfs writes between
1612	 * device_add and dev_pm_qos_add_request
1613	 */
1614	if (!dev_pm_qos_request_active(&df->user_max_freq_req))
1615		return -EINVAL;
1616
1617	ret = sscanf(buf, "%lu", &value);
1618	if (ret != 1)
1619		return -EINVAL;
1620
1621	/*
1622	 * PM QoS frequencies are in kHz so we need to convert. Convert by
1623	 * rounding upwards so that the acceptable interval never shrinks.
1624	 *
1625	 * For example if the user writes "666666666" to sysfs this value will
1626	 * be converted to 666667 kHz and back to 666667000 Hz before an OPP
1627	 * lookup, this ensures that an OPP of 666666666Hz is still accepted.
1628	 *
1629	 * A value of zero means "no limit".
1630	 */
1631	if (value)
1632		value = DIV_ROUND_UP(value, HZ_PER_KHZ);
1633	else
1634		value = PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE;
1635
1636	ret = dev_pm_qos_update_request(&df->user_max_freq_req, value);
1637	if (ret < 0)
1638		return ret;
1639
1640	return count;
1641}
1642
1643static ssize_t max_freq_show(struct device *dev, struct device_attribute *attr,
1644			     char *buf)
1645{
1646	struct devfreq *df = to_devfreq(dev);
1647	unsigned long min_freq, max_freq;
1648
1649	mutex_lock(&df->lock);
1650	devfreq_get_freq_range(df, &min_freq, &max_freq);
1651	mutex_unlock(&df->lock);
1652
1653	return sprintf(buf, "%lu\n", max_freq);
1654}
1655static DEVICE_ATTR_RW(max_freq);
1656
1657static ssize_t available_frequencies_show(struct device *d,
1658					  struct device_attribute *attr,
1659					  char *buf)
1660{
1661	struct devfreq *df = to_devfreq(d);
1662	ssize_t count = 0;
1663	int i;
1664
1665	if (!df->profile)
1666		return -EINVAL;
1667
1668	mutex_lock(&df->lock);
1669
1670	for (i = 0; i < df->max_state; i++)
1671		count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
1672				"%lu ", df->freq_table[i]);
1673
1674	mutex_unlock(&df->lock);
1675	/* Truncate the trailing space */
1676	if (count)
1677		count--;
1678
1679	count += sprintf(&buf[count], "\n");
1680
1681	return count;
1682}
1683static DEVICE_ATTR_RO(available_frequencies);
1684
1685static ssize_t trans_stat_show(struct device *dev,
1686			       struct device_attribute *attr, char *buf)
1687{
1688	struct devfreq *df = to_devfreq(dev);
1689	ssize_t len;
1690	int i, j;
1691	unsigned int max_state;
1692
1693	if (!df->profile)
1694		return -EINVAL;
1695	max_state = df->max_state;
1696
1697	if (max_state == 0)
1698		return sprintf(buf, "Not Supported.\n");
1699
1700	mutex_lock(&df->lock);
1701	if (!df->stop_polling &&
1702			devfreq_update_status(df, df->previous_freq)) {
1703		mutex_unlock(&df->lock);
1704		return 0;
1705	}
1706	mutex_unlock(&df->lock);
1707
1708	len = sprintf(buf, "     From  :   To\n");
1709	len += sprintf(buf + len, "           :");
1710	for (i = 0; i < max_state; i++)
1711		len += sprintf(buf + len, "%10lu",
1712				df->freq_table[i]);
1713
1714	len += sprintf(buf + len, "   time(ms)\n");
1715
1716	for (i = 0; i < max_state; i++) {
1717		if (df->freq_table[i] == df->previous_freq)
 
1718			len += sprintf(buf + len, "*");
1719		else
1720			len += sprintf(buf + len, " ");
1721
1722		len += sprintf(buf + len, "%10lu:", df->freq_table[i]);
 
1723		for (j = 0; j < max_state; j++)
1724			len += sprintf(buf + len, "%10u",
1725				df->stats.trans_table[(i * max_state) + j]);
1726
1727		len += sprintf(buf + len, "%10llu\n", (u64)
1728			jiffies64_to_msecs(df->stats.time_in_state[i]));
1729	}
1730
1731	len += sprintf(buf + len, "Total transition : %u\n",
1732					df->stats.total_trans);
1733	return len;
1734}
1735
1736static ssize_t trans_stat_store(struct device *dev,
1737				struct device_attribute *attr,
1738				const char *buf, size_t count)
1739{
1740	struct devfreq *df = to_devfreq(dev);
1741	int err, value;
1742
1743	if (!df->profile)
1744		return -EINVAL;
1745
1746	if (df->max_state == 0)
1747		return count;
1748
1749	err = kstrtoint(buf, 10, &value);
1750	if (err || value != 0)
1751		return -EINVAL;
1752
1753	mutex_lock(&df->lock);
1754	memset(df->stats.time_in_state, 0, (df->max_state *
1755					sizeof(*df->stats.time_in_state)));
1756	memset(df->stats.trans_table, 0, array3_size(sizeof(unsigned int),
1757					df->max_state,
1758					df->max_state));
1759	df->stats.total_trans = 0;
1760	df->stats.last_update = get_jiffies_64();
1761	mutex_unlock(&df->lock);
1762
1763	return count;
1764}
1765static DEVICE_ATTR_RW(trans_stat);
1766
1767static struct attribute *devfreq_attrs[] = {
1768	&dev_attr_name.attr,
1769	&dev_attr_governor.attr,
1770	&dev_attr_available_governors.attr,
1771	&dev_attr_cur_freq.attr,
1772	&dev_attr_available_frequencies.attr,
1773	&dev_attr_target_freq.attr,
1774	&dev_attr_min_freq.attr,
1775	&dev_attr_max_freq.attr,
1776	&dev_attr_trans_stat.attr,
1777	NULL,
1778};
1779ATTRIBUTE_GROUPS(devfreq);
1780
1781static ssize_t polling_interval_show(struct device *dev,
1782				     struct device_attribute *attr, char *buf)
1783{
1784	struct devfreq *df = to_devfreq(dev);
1785
1786	if (!df->profile)
1787		return -EINVAL;
1788
1789	return sprintf(buf, "%d\n", df->profile->polling_ms);
1790}
1791
1792static ssize_t polling_interval_store(struct device *dev,
1793				      struct device_attribute *attr,
1794				      const char *buf, size_t count)
1795{
1796	struct devfreq *df = to_devfreq(dev);
1797	unsigned int value;
1798	int ret;
1799
1800	if (!df->governor)
1801		return -EINVAL;
1802
1803	ret = sscanf(buf, "%u", &value);
1804	if (ret != 1)
1805		return -EINVAL;
1806
1807	df->governor->event_handler(df, DEVFREQ_GOV_UPDATE_INTERVAL, &value);
1808	ret = count;
1809
1810	return ret;
1811}
1812static DEVICE_ATTR_RW(polling_interval);
1813
1814static ssize_t timer_show(struct device *dev,
1815			     struct device_attribute *attr, char *buf)
1816{
1817	struct devfreq *df = to_devfreq(dev);
1818
1819	if (!df->profile)
1820		return -EINVAL;
1821
1822	return sprintf(buf, "%s\n", timer_name[df->profile->timer]);
1823}
1824
1825static ssize_t timer_store(struct device *dev, struct device_attribute *attr,
1826			      const char *buf, size_t count)
1827{
1828	struct devfreq *df = to_devfreq(dev);
1829	char str_timer[DEVFREQ_NAME_LEN + 1];
1830	int timer = -1;
1831	int ret = 0, i;
1832
1833	if (!df->governor || !df->profile)
1834		return -EINVAL;
1835
1836	ret = sscanf(buf, "%16s", str_timer);
1837	if (ret != 1)
1838		return -EINVAL;
1839
1840	for (i = 0; i < DEVFREQ_TIMER_NUM; i++) {
1841		if (!strncmp(timer_name[i], str_timer, DEVFREQ_NAME_LEN)) {
1842			timer = i;
1843			break;
1844		}
1845	}
1846
1847	if (timer < 0) {
1848		ret = -EINVAL;
1849		goto out;
1850	}
1851
1852	if (df->profile->timer == timer) {
1853		ret = 0;
1854		goto out;
1855	}
1856
1857	mutex_lock(&df->lock);
1858	df->profile->timer = timer;
1859	mutex_unlock(&df->lock);
1860
1861	ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
1862	if (ret) {
1863		dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
1864			 __func__, df->governor->name, ret);
1865		goto out;
1866	}
1867
1868	ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
1869	if (ret)
1870		dev_warn(dev, "%s: Governor %s not started(%d)\n",
1871			 __func__, df->governor->name, ret);
1872out:
1873	return ret ? ret : count;
1874}
1875static DEVICE_ATTR_RW(timer);
1876
1877#define CREATE_SYSFS_FILE(df, name)					\
1878{									\
1879	int ret;							\
1880	ret = sysfs_create_file(&df->dev.kobj, &dev_attr_##name.attr);	\
1881	if (ret < 0) {							\
1882		dev_warn(&df->dev,					\
1883			"Unable to create attr(%s)\n", "##name");	\
1884	}								\
1885}									\
1886
1887/* Create the specific sysfs files which depend on each governor. */
1888static void create_sysfs_files(struct devfreq *devfreq,
1889				const struct devfreq_governor *gov)
1890{
1891	if (IS_SUPPORTED_ATTR(gov->attrs, POLLING_INTERVAL))
1892		CREATE_SYSFS_FILE(devfreq, polling_interval);
1893	if (IS_SUPPORTED_ATTR(gov->attrs, TIMER))
1894		CREATE_SYSFS_FILE(devfreq, timer);
1895}
1896
1897/* Remove the specific sysfs files which depend on each governor. */
1898static void remove_sysfs_files(struct devfreq *devfreq,
1899				const struct devfreq_governor *gov)
1900{
1901	if (IS_SUPPORTED_ATTR(gov->attrs, POLLING_INTERVAL))
1902		sysfs_remove_file(&devfreq->dev.kobj,
1903				&dev_attr_polling_interval.attr);
1904	if (IS_SUPPORTED_ATTR(gov->attrs, TIMER))
1905		sysfs_remove_file(&devfreq->dev.kobj, &dev_attr_timer.attr);
1906}
1907
1908/**
1909 * devfreq_summary_show() - Show the summary of the devfreq devices
1910 * @s:		seq_file instance to show the summary of devfreq devices
1911 * @data:	not used
1912 *
1913 * Show the summary of the devfreq devices via 'devfreq_summary' debugfs file.
1914 * It helps that user can know the detailed information of the devfreq devices.
1915 *
1916 * Return 0 always because it shows the information without any data change.
1917 */
1918static int devfreq_summary_show(struct seq_file *s, void *data)
1919{
1920	struct devfreq *devfreq;
1921	struct devfreq *p_devfreq = NULL;
1922	unsigned long cur_freq, min_freq, max_freq;
1923	unsigned int polling_ms;
1924	unsigned int timer;
1925
1926	seq_printf(s, "%-30s %-30s %-15s %-10s %10s %12s %12s %12s\n",
1927			"dev",
1928			"parent_dev",
1929			"governor",
1930			"timer",
1931			"polling_ms",
1932			"cur_freq_Hz",
1933			"min_freq_Hz",
1934			"max_freq_Hz");
1935	seq_printf(s, "%30s %30s %15s %10s %10s %12s %12s %12s\n",
1936			"------------------------------",
1937			"------------------------------",
1938			"---------------",
1939			"----------",
1940			"----------",
1941			"------------",
1942			"------------",
1943			"------------");
1944
1945	mutex_lock(&devfreq_list_lock);
1946
1947	list_for_each_entry_reverse(devfreq, &devfreq_list, node) {
1948#if IS_ENABLED(CONFIG_DEVFREQ_GOV_PASSIVE)
1949		if (!strncmp(devfreq->governor->name, DEVFREQ_GOV_PASSIVE,
1950							DEVFREQ_NAME_LEN)) {
1951			struct devfreq_passive_data *data = devfreq->data;
1952
1953			if (data)
1954				p_devfreq = data->parent;
1955		} else {
1956			p_devfreq = NULL;
1957		}
1958#endif
1959
1960		mutex_lock(&devfreq->lock);
1961		cur_freq = devfreq->previous_freq;
1962		devfreq_get_freq_range(devfreq, &min_freq, &max_freq);
1963		timer = devfreq->profile->timer;
1964
1965		if (IS_SUPPORTED_ATTR(devfreq->governor->attrs, POLLING_INTERVAL))
1966			polling_ms = devfreq->profile->polling_ms;
1967		else
1968			polling_ms = 0;
1969		mutex_unlock(&devfreq->lock);
1970
1971		seq_printf(s,
1972			"%-30s %-30s %-15s %-10s %10d %12ld %12ld %12ld\n",
1973			dev_name(&devfreq->dev),
1974			p_devfreq ? dev_name(&p_devfreq->dev) : "null",
1975			devfreq->governor->name,
1976			polling_ms ? timer_name[timer] : "null",
1977			polling_ms,
1978			cur_freq,
1979			min_freq,
1980			max_freq);
1981	}
1982
1983	mutex_unlock(&devfreq_list_lock);
1984
1985	return 0;
1986}
1987DEFINE_SHOW_ATTRIBUTE(devfreq_summary);
1988
1989static int __init devfreq_init(void)
1990{
1991	devfreq_class = class_create(THIS_MODULE, "devfreq");
1992	if (IS_ERR(devfreq_class)) {
1993		pr_err("%s: couldn't create class\n", __FILE__);
1994		return PTR_ERR(devfreq_class);
1995	}
1996
1997	devfreq_wq = create_freezable_workqueue("devfreq_wq");
1998	if (!devfreq_wq) {
1999		class_destroy(devfreq_class);
2000		pr_err("%s: couldn't create workqueue\n", __FILE__);
2001		return -ENOMEM;
2002	}
2003	devfreq_class->dev_groups = devfreq_groups;
2004
2005	devfreq_debugfs = debugfs_create_dir("devfreq", NULL);
2006	debugfs_create_file("devfreq_summary", 0444,
2007				devfreq_debugfs, NULL,
2008				&devfreq_summary_fops);
2009
2010	return 0;
2011}
2012subsys_initcall(devfreq_init);
2013
2014/*
2015 * The following are helper functions for devfreq user device drivers with
2016 * OPP framework.
2017 */
2018
2019/**
2020 * devfreq_recommended_opp() - Helper function to get proper OPP for the
2021 *			     freq value given to target callback.
2022 * @dev:	The devfreq user device. (parent of devfreq)
2023 * @freq:	The frequency given to target function
2024 * @flags:	Flags handed from devfreq framework.
2025 *
2026 * The callers are required to call dev_pm_opp_put() for the returned OPP after
2027 * use.
2028 */
2029struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
2030					   unsigned long *freq,
2031					   u32 flags)
2032{
2033	struct dev_pm_opp *opp;
2034
2035	if (flags & DEVFREQ_FLAG_LEAST_UPPER_BOUND) {
2036		/* The freq is an upper bound. opp should be lower */
2037		opp = dev_pm_opp_find_freq_floor(dev, freq);
2038
2039		/* If not available, use the closest opp */
2040		if (opp == ERR_PTR(-ERANGE))
2041			opp = dev_pm_opp_find_freq_ceil(dev, freq);
2042	} else {
2043		/* The freq is an lower bound. opp should be higher */
2044		opp = dev_pm_opp_find_freq_ceil(dev, freq);
2045
2046		/* If not available, use the closest opp */
2047		if (opp == ERR_PTR(-ERANGE))
2048			opp = dev_pm_opp_find_freq_floor(dev, freq);
2049	}
2050
2051	return opp;
2052}
2053EXPORT_SYMBOL(devfreq_recommended_opp);
2054
2055/**
2056 * devfreq_register_opp_notifier() - Helper function to get devfreq notified
2057 *				     for any changes in the OPP availability
2058 *				     changes
2059 * @dev:	The devfreq user device. (parent of devfreq)
2060 * @devfreq:	The devfreq object.
2061 */
2062int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq)
2063{
2064	return dev_pm_opp_register_notifier(dev, &devfreq->nb);
2065}
2066EXPORT_SYMBOL(devfreq_register_opp_notifier);
2067
2068/**
2069 * devfreq_unregister_opp_notifier() - Helper function to stop getting devfreq
2070 *				       notified for any changes in the OPP
2071 *				       availability changes anymore.
2072 * @dev:	The devfreq user device. (parent of devfreq)
2073 * @devfreq:	The devfreq object.
2074 *
2075 * At exit() callback of devfreq_dev_profile, this must be included if
2076 * devfreq_recommended_opp is used.
2077 */
2078int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq)
2079{
2080	return dev_pm_opp_unregister_notifier(dev, &devfreq->nb);
2081}
2082EXPORT_SYMBOL(devfreq_unregister_opp_notifier);
2083
2084static void devm_devfreq_opp_release(struct device *dev, void *res)
2085{
2086	devfreq_unregister_opp_notifier(dev, *(struct devfreq **)res);
2087}
2088
2089/**
2090 * devm_devfreq_register_opp_notifier() - Resource-managed
2091 *					  devfreq_register_opp_notifier()
2092 * @dev:	The devfreq user device. (parent of devfreq)
2093 * @devfreq:	The devfreq object.
2094 */
2095int devm_devfreq_register_opp_notifier(struct device *dev,
2096				       struct devfreq *devfreq)
2097{
2098	struct devfreq **ptr;
2099	int ret;
2100
2101	ptr = devres_alloc(devm_devfreq_opp_release, sizeof(*ptr), GFP_KERNEL);
2102	if (!ptr)
2103		return -ENOMEM;
2104
2105	ret = devfreq_register_opp_notifier(dev, devfreq);
2106	if (ret) {
2107		devres_free(ptr);
2108		return ret;
2109	}
2110
2111	*ptr = devfreq;
2112	devres_add(dev, ptr);
2113
2114	return 0;
2115}
2116EXPORT_SYMBOL(devm_devfreq_register_opp_notifier);
2117
2118/**
2119 * devm_devfreq_unregister_opp_notifier() - Resource-managed
2120 *					    devfreq_unregister_opp_notifier()
2121 * @dev:	The devfreq user device. (parent of devfreq)
2122 * @devfreq:	The devfreq object.
2123 */
2124void devm_devfreq_unregister_opp_notifier(struct device *dev,
2125					 struct devfreq *devfreq)
2126{
2127	WARN_ON(devres_release(dev, devm_devfreq_opp_release,
2128			       devm_devfreq_dev_match, devfreq));
2129}
2130EXPORT_SYMBOL(devm_devfreq_unregister_opp_notifier);
2131
2132/**
2133 * devfreq_register_notifier() - Register a driver with devfreq
2134 * @devfreq:	The devfreq object.
2135 * @nb:		The notifier block to register.
2136 * @list:	DEVFREQ_TRANSITION_NOTIFIER.
2137 */
2138int devfreq_register_notifier(struct devfreq *devfreq,
2139			      struct notifier_block *nb,
2140			      unsigned int list)
2141{
2142	int ret = 0;
2143
2144	if (!devfreq)
2145		return -EINVAL;
2146
2147	switch (list) {
2148	case DEVFREQ_TRANSITION_NOTIFIER:
2149		ret = srcu_notifier_chain_register(
2150				&devfreq->transition_notifier_list, nb);
2151		break;
2152	default:
2153		ret = -EINVAL;
2154	}
2155
2156	return ret;
2157}
2158EXPORT_SYMBOL(devfreq_register_notifier);
2159
2160/*
2161 * devfreq_unregister_notifier() - Unregister a driver with devfreq
2162 * @devfreq:	The devfreq object.
2163 * @nb:		The notifier block to be unregistered.
2164 * @list:	DEVFREQ_TRANSITION_NOTIFIER.
2165 */
2166int devfreq_unregister_notifier(struct devfreq *devfreq,
2167				struct notifier_block *nb,
2168				unsigned int list)
2169{
2170	int ret = 0;
2171
2172	if (!devfreq)
2173		return -EINVAL;
2174
2175	switch (list) {
2176	case DEVFREQ_TRANSITION_NOTIFIER:
2177		ret = srcu_notifier_chain_unregister(
2178				&devfreq->transition_notifier_list, nb);
2179		break;
2180	default:
2181		ret = -EINVAL;
2182	}
2183
2184	return ret;
2185}
2186EXPORT_SYMBOL(devfreq_unregister_notifier);
2187
2188struct devfreq_notifier_devres {
2189	struct devfreq *devfreq;
2190	struct notifier_block *nb;
2191	unsigned int list;
2192};
2193
2194static void devm_devfreq_notifier_release(struct device *dev, void *res)
2195{
2196	struct devfreq_notifier_devres *this = res;
2197
2198	devfreq_unregister_notifier(this->devfreq, this->nb, this->list);
2199}
2200
2201/**
2202 * devm_devfreq_register_notifier()
2203 *	- Resource-managed devfreq_register_notifier()
2204 * @dev:	The devfreq user device. (parent of devfreq)
2205 * @devfreq:	The devfreq object.
2206 * @nb:		The notifier block to be unregistered.
2207 * @list:	DEVFREQ_TRANSITION_NOTIFIER.
2208 */
2209int devm_devfreq_register_notifier(struct device *dev,
2210				struct devfreq *devfreq,
2211				struct notifier_block *nb,
2212				unsigned int list)
2213{
2214	struct devfreq_notifier_devres *ptr;
2215	int ret;
2216
2217	ptr = devres_alloc(devm_devfreq_notifier_release, sizeof(*ptr),
2218				GFP_KERNEL);
2219	if (!ptr)
2220		return -ENOMEM;
2221
2222	ret = devfreq_register_notifier(devfreq, nb, list);
2223	if (ret) {
2224		devres_free(ptr);
2225		return ret;
2226	}
2227
2228	ptr->devfreq = devfreq;
2229	ptr->nb = nb;
2230	ptr->list = list;
2231	devres_add(dev, ptr);
2232
2233	return 0;
2234}
2235EXPORT_SYMBOL(devm_devfreq_register_notifier);
2236
2237/**
2238 * devm_devfreq_unregister_notifier()
2239 *	- Resource-managed devfreq_unregister_notifier()
2240 * @dev:	The devfreq user device. (parent of devfreq)
2241 * @devfreq:	The devfreq object.
2242 * @nb:		The notifier block to be unregistered.
2243 * @list:	DEVFREQ_TRANSITION_NOTIFIER.
2244 */
2245void devm_devfreq_unregister_notifier(struct device *dev,
2246				      struct devfreq *devfreq,
2247				      struct notifier_block *nb,
2248				      unsigned int list)
2249{
2250	WARN_ON(devres_release(dev, devm_devfreq_notifier_release,
2251			       devm_devfreq_dev_match, devfreq));
2252}
2253EXPORT_SYMBOL(devm_devfreq_unregister_notifier);